1. Field of the Invention
The present invention generally concerns vehicular safety, including control of a vehicle's brakes and/or brake lights.
The present invention particularly concerns a (i) camera- and (ii) microprocessor-based system for sensing and interpreting brake lights to the forward of a subject vehicle.
The present invention further particularly concerns the criteria relevant to the sensing of (i) brake lights to the forward of a subject vehicle, and also (ii) the distance(s) of separation, and (iii) the rate(s) of change in this (these) distance(s) of separation.
The present invention still further particularly concerns the appropriate combination of sensed conditions, including such sensed conditions as may each have some degree of uncertainty, as will desirably occasion activation of the brake lights and/or brakes of the subject vehicle.
The present invention yet still further particularly concerns (i) the interplay between the differing circumstances as may occasion the activation of the brake lights and/or brakes of a subject vehicle, and (ii) the interaction between an advanced system of brake lights and/or brakes activation on this subject vehicle with all other vehicles on the highway, both equipped and un-equipped with the same or with similar systems, including during vehicle platooning.
2. Description of the Prior Art
2.1 Vehicular Rear End Collisions
As reported by True Indications Corporation, Granite Bay, Calif. at their web site <www.brake-alert.com>, tremendous progress has been made in the last few decades in vehicle safety.
Improvements in passive safety features such as seat belts, air bags, crush zones, visibility, and lighting have dramatically reduced the accident fatality rate in the U.S. For example, the fatality rate per hundred million vehicle miles traveled has fallen from 5.5 to 1.7 in the period from the mid 1960's to 1997.
However, each year motor vehicle crashes in the U.S. still account for a staggering 45,000 deaths, more than three million injuries, and $137 billion in financial losses. Accident data collected by the U.S. National Highway Transportation Safety Administration (NHTSA) show that about 88% of rear end collisions are caused by driver inattention and following too closely. See Knipling, R., et al., “Rear End Crashes: Problem Size Assessment and Statistical Description,”; NHTSA Technical Report, Springfield, Va., 1993.
Since rear-end collisions are based on human factors, any machine system that could compensate for, or alleviate, the consequences of driver inattentiveness and/or misjudgment in following too closely would be desirable. In this regard certain model year 2000 Mercedes Benz automobiles exhibit a special response when “panic braking” is sensed responsive to the driver's rapid plunge of the brake petal. Sensing such a condition, the Mercedes car will proceed to apply its own brakes faster than its driver ever could.
However, advance warning of collision and/or risk of collision is preferred, especially if sufficiently timely so as to couple the attention and judgment of the driver by alerting him or her to an incipient collision. In this regard collision avoidance and proximity detection systems for automobiles exist in the prior art. However, the infrequent exercise, potential for both false positives (collision predicted where none occurs), and false negatives (collision which in fact occurs is not predicted) of these systems make that these systems have not yet (circa 2000) been widely adopted. It would accordingly be desirable if some vehicle system serving to regularly reliably alert a driver to even the enhanced risk or possibility of collision could be developed.
If the driver could see, or otherwise learn, the response of such a system to “near misses”, then the driver could come to appreciate, and respond to, the indications of the system—much as an airline pilot learns to respond to the “pull up; pull up” audio ground proximity warning, or the stall speed audio tone warning, of an airplane flight system.
2.2 A Severe Braking Indicator for Vehicles
In one less preferred variant of the brake light and/or brake activation system of the present invention, the system will be seen to optionally function so as to generate a braking signal that is flashing. It will be seen to be possible in the present invention that this optionally flashing indication can be ascribed to have some particular meaning. For example, a flashing brake light signal can mean, by way of example, that a brake light has been sensed to the fore while the vehicle in which the system of the present invention is installed is traveling more than some preset speed, for example more than forty miles per hour (40 m.p.h.). For example, a flashing brake light can mean that a obstacle, whether moving or not, has been detected within a preset range to the forward of the vehicle. For example, a flashing brake light can mean that the vehicle is experiencing a rate of closure with a vehicle or other potential obstacle to the fore in excess of some predetermined threshold rate.
Many other sensed conditions, and combinations of sensed conditions, will be seen to be suitable of combination with the primary sensed condition of the system and of the method of the present invention where the application of brake lights to the fore of a vehicle is sensed. However, for purposes of review of the prior art in the present section 2.2, it is sufficient simply to note that brake lights that are differentiated in accordance with certain sensed conditions already exist, and that these more sophisticated renditions of the standard brake light signal are apparently beneficial, or at least not deleterious, to safety.
An example of a previous production of a non-standard brake light signal is provided by True Indications Corporation, Granite Bay, Calif. The True Indications Corporation internet web site is: <www.brake-alert.com>. The Brake Alert™ (Brake Alert™ is a registered trademark of True Indications) safety device of True Indications is directed to helping reduce rear end collisions. On the premise—agreed to by the inventor of the present invention—that the best kind of safety device is one that helps prevent a collision from occurring, True Indications has developed an electronic control module that senses when a vehicle brakes severely. This device connects to the center third brake light. When a vehicle stops quickly, the control module senses the severe deceleration of the vehicle and begins to flash the third brake light at a fast rate. The flashing brake light informs the driver behind the decelerating vehicle that the leading vehicle is braking very hard (greater than 0.3 G or when the seat belt retractor locks). The third brake light still turns on steadily with normal braking, but flashes only when severe braking occurs. This early indication from the flashing brake light provides an early warning that the leading vehicle is doing some kind of emergency braking. This gives the vehicle following behind extra moments to take evasive action, e.g. brake immediately, change lanes, etc. A rear end collision is most likely caused by a vehicle stopping quickly. True Indications' Brake Alert control module senses when a vehicle is stopping quickly and immediately changes the third brake light's steady illumination to an eye-catching fast blinking light.
If the braking vehicle reduces its deceleration to less than 0.3 G, the third brake light will resume to a steady illumination. It is asserted that a driver behind a vehicle with Brake Alert system can get information about the vehicle's situation much sooner. A driver no longer has to “perceive” that the vehicle in front of him is stopping at a fast rate. It is further asserted that when Brake Alert system flashes the third brake light, the driver behind will know immediately that the vehicle in front is stopping quickly.
The manufacturer asserts that the Brake Alert system can be extremely helpful in rainy conditions when the streets are wet and a driver needs more stopping distance. A driver can also be informed earlier in foggy conditions that the vehicle in front of him is stopping quickly. It is asserted that the Brake Alert signal cuts through the fog and is visible at great distances. This early warning is especially important on highways where chain reaction pile ups can be avoided. As each drivers stops quickly, the driver behind gets immediate information from the flashing light. Since each driver is applying their brakes sooner, it effectively diffuses the situation of a possible multi-vehicle pile up.
The Brake Alert system is claimed to be even more effective when it is connected to the new bright LED (Light Emitting Diodes) third brake lights. These are usually located within rear spoilers or on top of mini-vans or sports utility vehicles. LEDs have fast turn on and turn off times which attract more attention to the severely braking vehicle. With either incandescent lamps or LEDs, the BRAKE ALERT warning system is directed to informing drivers behind a vehicle in which the system is installed that the vehicle is stopping quickly, potentially benefitting both vehicles. Accident statistics and numerical analysis strongly suggest that this type of warning system can be effective to help prevent rear end collisions.